Load carriers for vehicles are widely used to provide the vehicles, such as automobiles, with an increased loading capacity. A load carrier is usually mounted on the vehicles tow hook, an equivalent position at the rear of the vehicle, or on roof racks. Wherever the load carrier is mounted, there is a need to readily secure the bicycle to the load carrier especially before transportation of the bicycle in traffic environments. A bicycle which is accidentally detached from the load carrier during transportation could cause severe damage
Support assemblies for securing a bicycle to a load carrier for a vehicle are widely used together with load carriers for bicycles. It is common that support assemblies use a clamping jaw to secure the bicycle to the support assembly. One such support assembly is disclosed in the International patent application no. WO 2005/065817 Thule Sweden AB. The clamping jaw of the support assembly comprises a first and a second jaw member which upon tightening with a tightening device, such as a rotating knob, are pressed together about a portion of a bicycle, usually the frame of the bicycle, to secure the bicycle to the load carrier. It is the mouth ribs, i.e. side edges, of the jaw members which engage the bicycle to retain the bicycle to the load carrier.
A clamping jaw of a support assembly can be manufactured in a wide variety of different ways. It has become more common lately to manufacture the clamping jaw from a plastic material e.g. by form molding the two jaw members for example. To provide structural integrity to a jaw member, the jaw member in the WO 2009/065817 document is formed by a frame work structure in terms of that the jaw member comprises a plurality of ribs which project from the outer housing and towards the interior of the jaw member and supportive ribs extending between the side edges of the jaw member. The inside of the “mouth” of the clamping jaw thus has a plurality of exposed ribs. A grip section can be formed at the center section of the jaw member by filling the cavities, or grooves, formed by the frame work structure with a soft thermoplastic polymer. It requires a large amount of thermoplastic polymers to fill the void formed by the frame work structure to provide a reasonable grip section which further adds weight to the clamping jaw.
There is a need for the clamping jaws of the support assemblies and its individual components to withstand a high amount of crash violence. Crash violence is a term for describing the forces imparted to the components during an accident with the vehicle, such as a crash or a collision scenario with another vehicle. During a crash or a collision, the vehicle, the bicycle carrier and of course the support assembly retaining the bicycle to the bicycle carrier is subjected to an extreme amount of crash violence. It has been found that clamping jaws of support assemblies can accidentally break during such high levels of stress, especially when mounted to larger bicycles. In order to overcome this problem clamping jaws are made stronger by increasing the thickness of the material of the clamping jaw. This however makes the clamping jaws bigger and clumsier and more difficult to mount to bicycles as these sometimes tend to have a limited amount of space available for the clamping jaw.
It has been found that during a crash or a collision scenario, at least one of the jaw members of the clamping jaw of a support assembly is especially vulnerable when subjected to high tensile stress. The tensile stress is generally as highest in the mouth of the clamping jaw, i.e. on the bicycle facing side. With reference to a cross section of the jaw member at the center of the mouth, the tensile stress is gradually decreasing closer to the centre of gravity of the cross section and will transcend to a compression stress towards the distal end of the structure.
It has now been found that clamping jaws of the aforementioned kind have some disadvantages. If a clamping jaw having a frame work structure needs to be very rigid they tend to become very large and very heavy, and thus not very user friendly nor easy to mount to ta bicycle.
The support assembly disclosed in the WO 2009/065817 document comprises a rotateable knob connected to an axle to impart the first and the second jaw members of the clamping jaw with a force to press the jaws together. The axle extends to an opposing end of the support assembly comprising an annular clamp which counteracts the rotating motion of the knob to press the first and the second jaw member together.
There is however always a risk of the user imparts the knob with a too high torque and thus accidentally damages the bicycle. Some support assemblies are thus provided with a torque limiting mechanism to limit the amount of transferrable torque to the clamping jaw via the knob. One such support assembly is disclosed in the European patent application no. EP 2,230,412 A1.
To prevent or significantly reduce the risk of theft of bicycles, support assemblies for load carriers can be provided with locks. The support assembly disclosed in the European patent application no. EP 2,230,412 A1 also comprises a lock mechanism which is cooperating with the torque limiting mechanism to lock or unlock the support assembly. The solution disclosed in the latter document is however associated with a number of drawbacks. The lock mechanism is quite complex due to the configuration of the torque limiting mechanism.